Northwestern  University 

The  Graduate  School 
Department  of  Chemistry 


y  mo 


The  Structure  of  Maltose  and  Its 
Oxidation  Products  with  Al- 
kaline Peroxide  of 
Hydrogen 


SUBMITTED  TO  THE  BOARD  OF  GRADUATE  STUDIES  IN  CANDIDACY 
FOR  THE  DEGREE  OF  DOCTOR  OF  PHILOSOPHY 


BY 


SIEGEL  A.  BUCKBOROUGH 


ESCHENBACH 


EASTON, 


1914 


.,> 


Northwestern  University 

The  Graduate  School 
Department  of  Chemistry 


The  Structure  of  Maltose  and  Its 
Oxidation  Products  with  Al- 
kaline Peroxide  of 
Hydrogen 


A  DISSERTATION 

SUBMITTED  TO  THE  BOARD  OF  GRADUATE  STUDIES  IN  CANDIDACY 
FOR  THE  DEGREE  OF  DOCTOR  OF  PHILOSOPHY 


BY  i 

SIEGEL  A.  BUCKBOROUGH 


EASTON,  PA.: 

ESCHENBACH  PRINTING  COMPANY 
1914 


The  Structure  of  Maltose  and  Its  Oxidation  Products  with 
Alkaline  Peroxide  of  Hydrogen, 


Nef1  and  his  students  have  established  the  methods  for  oxidizing  the 
sugars  with  various  agents  and  for  separating  and  identifying  the  resulting 
products.  Nef2  has  recently  submitted  a  complete  system  of  dissociation 
of  the  sugar  molecule  in  explanation  of  these  oxidations  and  in  explana- 
tion of  the  reciprocal  conversion  of  certain  sugars  under  the  influence  of 
dilute  alkalies. 

Lewis3  investigated  the  products  formed  when  maltose  is  oxidized 
with  alkaline  cupric  sulfate.  This  work  brought  out  that  maltose  is 
oxidized  largely  as  an  unhydrolyzed  disaccharose,  forming  glucosido- 
acids,  whose  subsequent  hydrolysis  gives  dextrose  and  simpler  acids. 
There  were  thus  obtained  from  100  g.  of  anhydrous  maltose,  34.72  g.  of 
hydrolyzed  dextrose,  29.78  g.  of  hexonic  acids,  2.86  g.  of  glycollic,  0.25 
g.  of  oxalic,  3.46  g.  of  formic  acids,  and  7.74  g.  of  carbon  dioxide.  Of 
unidentified  material,  believed  to  contain  glycerinic  and  trioxybutyric 
acids,  there  remained  27.29  g.,  with  2.15  g.  lost  during  the  various 
manipulations.  The  ratio  of  the  various  products  found  was  quite 
different  from  that  observed  by  Nef4  in  a  study  of  the  oxidation  products 
of  the  simple  hexoses,  dextrose,  levulose,  and  mannose,  especially  in 
respect  to  the  larger  amount  of  mannonic  lactone  (21.00  g.)  formed  from 
the  disaccharose.  This  investigation  of  maltose,  however,  failed  to  throw 
any  light  on  the  constitution  of  that  sugar,  largely  because  the  amount 
of  oxygen  taken  up  by  each  molecule  was  insufficient. 

The  present  study  was  therefore  undertaken  in  the  hope  that  the  more 
complete  destruction  of  the  maltose  molecule,  under  the  influence  of 
alkaline  hydrogen  peroxide,  might  permit  a  better  quantitative  separation 
of  the  products,  thus  reflecting  the  point  of  the  glucosido  union  between 

1  Ann.,  357,  214-312;  376,  1-119;  4<>3.  204-383. 

2  Ibid.,  403,  204-242. 

3  Am.  Chem.  J.,  42,  301-319. 

4  Ann.,  357,  259. 


735244 


the  two  constituent  dextrose  groups  in  malt  sugar.  The  results  con- 
firmed the  previous  findings  that  maltose  oxidizes  largely  without  hy- 
drolysis and  that  saccharinic  acid  formation  does  not  take  place  under 
the  conditions.  A  larger  amount  of  oxygen  is  taken  up  with  alkaline 
peroxide  as  evidenced  in  the  larger  yield  of  acids  containing  few  carbon 
atoms.  One  hundred  grams  of  anhydrous  maltose  gave,  by  this  method, 
22.97  g-  °f  hydrolyzed  dextrose  (corr.  24.97  g.)  0.16  g.  of  mannonic  lactone, 
16.04  S-  °f  glycollic,  o.i i  g.  of  oxalic,  55.37  g.  of  formic  acid  and  4.44  g. 
of  carbon  dioxide.  Of  unidentified  material  there  remained  1.18  g., 
believed  to  contain  erythronic  and  /-threonic  acids.  One  gram  of  ma- 
terial was  used  up  in  titrations  and  otherwise  lost  in  manipulation. 
Especially  noteworthy  are  the  larger  amounts  of  formic  and  glycollic  acid 
found  in  comparison  with  the  previous  work  using  alkaline  copper  sulfate. 
Herein  it  is  believed  are  to  be  found  the  proofs  indicated  by  Nef1  which 
establish  the  structure  of  maltose  as  originally  assumed  by  Fischer,2  as 
a  7-d-glucosido-d-glucose  hydrate, 

-CH 1   CHO.HjO 


o 


CHOH 


CHOH 


-CH 


CHOH 


0 


CHOH 


CHOH 


CHOH 


CHOH 


CH2OH  I CH2, 

in  which  the  primary  alcohol  hydroxyl  functions  in  the  glucosido  union. 

Fischer3  established  the  structure  of  maltose3  as  a  disaccharose  com- 
posed of  two  molecules  of  d-glucose  and  containing  a  7-lactone  ring 
similar  to  his  synthetic  alkyl  •  glucosides.  According  to  Armstrong4 
maltose  is  an  a-glucoside,  as  established  by  selective  enzyme  action. 

5  4,3,2,1, 

The  resulting  formula  C6H10O5.CH2OH(CHOH)4.CHO.H2O  does  not, 
however,  determine  which  of  the  carbon  atoms  i,  2,  3,  4,  and  5,  holds  the 
hydroxyl  group  taking  part  in  the  glucosido  union.  Carbon  atoms  i, 
2  and  3  may  be  at  once  eliminated  as  possibilities  from  the  following 
consideration:  J-Maltose  with  iVa  molecules  of  calcium  hydroxide  at 
ordinary  temperature  gives  a  very  large  quantity  of  glucosido  a  and 
(3-(f-isosaccharinic  acids,5 

1  Ann.,  403,  299-303. 

2  Ber.,  27,  2988. 

3  Ibid.,  35,  3141;  28,  1145;  Nef,  Ann.,  403,  299. 
*  Trans.  Chem.  Soc.,  85,  1305. 

6  Kiliana,  Ber.,  18,  631,  2514;  38,  2668;  Nef,  Ann.,  357,  306;  376,  54~56. 


COOH  COOH 

I  I 

HO— C— CH2OH  CH2OH— C— OH 

I  I 

CH2  CH2 

!  I 

CHOH  CHOH 

I  I 

CHjOH  and  CH2OH 

This  product  can  only  come  about  through  enolization  of  malt  sugar 
with  subsequent  addition  and  splitting  off  of  water  forming  intermediately 

O 

I! 

7-d-glucosido-d-fructose,  C6H10O5.CH2OH(CHOH)3— C— CH2OH,  after 
the  analogy  of  the  interconversion  of  simple  hexoses  under  the  influence 
of  alkalies.1  This  product  similarly  goes  over  into  7-d-glucosido  ortho- 

O     O 

hexoson,  C6H10O5.CH2OHCHOHCH2— C— C— CH2OH,  which,  by  the 
benzilic  acid  rearrangement,  can  give  the  final  product  7-d-glucosido 
a-  and  /3-isosaccharinic  acids.  Hydrolysis  of  the  latter  yields  J-glucose 
and  a-  arid  /3-isosaccharin.  It  may  be  seen  that  these  transformations 
involve  the  three  hydroxyl  groups  attached  to  carbon  atoms  i,  2  and  3, 
which  therefore  must  be  present  as  such  in  the  original  maltose  molecule. 
The  participation  of  any  one  of  these  in  the  glucosido  union  is  therefore 
precluded. 

The  selection  of  the  correct  hydroxyl  group,  as  between  the  two  remain- 
ing, is  fixed  upon  that  attached  to  carbon  atom  6  by  the  following 
considerations : 

Nef 2  and  Glattfeld3  have  shown  that,  when  glucose  is  treated  with  alkali  of 
a  certain  concentration,  there  results  six  sugars;  i.  e.,  d-glucose,  d-mannose, 
d-fructose,  d-pseudofructose  and  a-  and  /3-d-glutose.  The  intermediate 
i,2-hexose  dienols  of  this  transformation  undergo  dissociation  into 
hydroxy  methylene  and  methyleneols  of  the  pentoses.  There  result, 
finally,  through  further  dissociation,  various  sugars  containing  one,  two, 
three,  four  and  five  carbon  atoms  (CH2O)X,  the  oxidation  of  which,  ac- 
companied in  some  instances  by  the  benzilic  acid  rearrangement,  produces 
the  ultimate  products  found  in  sugar  oxidation. 

It  is  altogether  probable  that  maltose  under  the  influence  of  alkalies 
enters  into  a  similar  equilibrium4  of  the  six  glucosido  hexoses  of  the 

glucose    series.     The    intermediate    glucosido    hexosedienols    undergoing 

• 

1  Ber.,  28,  3078;  Rec.  trav.  chim.  Pays-Bas.,  19,  i  (1900). 

2  Ann.,  403,  362. 

3  Am.  Chem.  J.,  50,  137. 

4  Nef,  Ann.,  403,  300,  381-382. 


dissociation,  oxidation,  etc.,  would  produce  the  glucosido  acids  whose 
hydrolysis  would  give  the  final  products  found  in  this  study. 

The  step-by-step  splitting  off  of  oxymethylene  with  the  formation  of 
formic  and  carbonic  acids,  as  the  main  course  of  the  reaction,  could  not 
go  beyond  the  carbon  atom  whose  hydroxyl  enters  into  the  glucosido 
union,  otherwise  glucosido  acids  would  not  be  the  principal  product  of 
the  oxidation.  In  the  following  equation  it  may  be  seen  that  if  Formula 
I  were  correct  for  maltose  the  principal  product  of  the  oxidation  would 
be  glucosido  glycerinic  acid : 

I. 

— CH—    — ! 


; 

_.n 

:HOH 

V 

( 

^nw.n 

:HOH 

D 

( 

:HOH    ( 

)    ( 

:HOH 

( 

:H 

CHOH 

( 

:HOH 

( 

:H 

0 


CHOH 
CHOH     O 

-CH  COOH 

I  I 

CHOH     I CH 

i  I 

CH2OH  CH2OH  CH2OH  CH2OH 

If  Formula  II  were  correct,   the  principal  product  would  be  glucosido 
glycollic  acid. 

II. 
i CH—  — i   CHO.H2O        i CH- 


O 


CHOH 


CHOH 


CHOH 


0 


CHOH 
CHOH 
CHOH 
CHOH 


n 


o 


CHOH 


CHOH 


-CH 


CHOH 


0 


COOH 


CH2OH     ' CH2  CH2OH     ' CH2 

One  hundred  grams  of  maltose  with  alkaline  peroxide  gave  finally  16.04 
g.  of  pure  crystalline  glycollic  acid  while  glycerinic  acid  was  not  found 
present. 

The  ratio  and  nature  of  the  oxidation  products  of  d-glucose  with  alkaline 
hydrogen  peroxide  are  quite  different  from  those  of  maltose,  especially 
in  respect  to  the  small  amount  of  glycollic  acid1  (4.3  from  100  g.)  and  the 
presence  of  d-arabonic  lactone2  in  the  former.  These  differences  must 
be  due  to  the  effect  of  the  above  glucosido  bond. 

Regarding  the  source  of  the  other  products  found,  the  large  quantities 

1  Spoehr,  Am.  Chem.  J.,  43,  238. 

2  Glattfeld,  Ibid.,  50,  135-157. 


of  carbonic  and  formic  acids  undoubtedly  result  from  the  oxidation  of 
dissociated  hydroxymethylene,  >CHOH.  Oxalic  acid  could  result 
from  a  more  complete  oxidation  of  diose  methyleneol,  HOCH^COHX.1 
Erythronic  and  /-threonic  acid  were  indicated  in  the  results  but  not 
established  because  of  the  small  amounts.  Their  formation  is  most 
probable  from  the  dissociation  of  glucosido  2,3-d-glucose  dienol, 

I CH 1     CH2OH 


CHOH 


CHOH 


o 


1 CH 


CHOH 


CH2OH 


COH 


COH 


HCOH 


HCOH 


-CH2 


into  the  methylenols  of  diose,  HOCH2C(OH)<,  and  of  glucosido-d- 
erythrose.  The  osone  of  the  latter,  formed  by  oxidation,  could  undergo 
the  benzilic  acid  rearrangement  (asymmetric  in  part  or  entire)  to  give 
C4  acids. 

Mannonic  lactone,  on  the  other  hand,  has  been  proved  to  arise  from  the 
hydrolysis  of  glucosido  mannonic  acid  through  the  action  of  dilute  alkalies 
on  maltosone.2  That  the  benzilic  acid  rearrangement  often  takes  place 
asymmetrically  has  been  pointed  out  by  Nef3  in  explanation  of  the  pre- 
ponderating gluconic  acid  in  oxidation  of  the  simple  hexoses  and  of 
mannonic  acid  when  maltose  is  acted  upon  by  Fehling's  solution. 
Lewis4  has  obtained  mannonic  lactone  in  quantity  from  the  oxidation  of 
lactose  with  Fehling's  solution.  In  the  oxidation  of  maltose  with  alkaline 
peroxide  there  is  formed  intermediately  therefore  some  maltosone. 

Experimental  Part. 

A  solution  of  3.22  g.  of  Kahlbaum's  maltose  in  80  cc.  of  3%  hydrogen  per- 
oxide (6.5  molecules)  was  prepared  and  added  with  vigorous  shaking  through 
a  period  of  ten  minutes  to  a  solution  of  5.62  g.  of  85.7%  potassium  hy- 
droxide (equivalent  to  4.82  g.  of  potassium  hydroxide  net,  being  7.7 
molecules)  in  100  cc.  of  water.  The  total  volume  was  then  increased  to 
200  cc.,  making  the  concentration  of  the  alkali  approximately  half  normal. 
Under  similar  conditions  3.22  g.  of  maltose  were  dissolved  in  160  cc. 
hydrogen  peroxide  and  the  mixture  poured  with  vigorous  shaking  through 
a  period  of  ten  minutes  into  a  solution  of  5.62  g.  of  potassium  hydroxide 
in  40  cc.  water.  . 

1  Cf.  Anderson,  Am.  Chem.  J.,  42,  406. 

2  Lewis,  Ibid.,  42,  315-319. 

3  Ann.,  357,  231-2,  284. 

4  Unpublished  notes. 


Three  solutions  of  each  concentration  were  prepared  and  kept  at  room 
temperature,  being  protected  from  the  carbon  dioxide  of  the  air  by  means 
of  soda  lime  tubes. 

In  none  of  the  above  mixtures  was  any  change  in  temperature  or  ap- 
pearance of  the  solution  noted.  The  final  solutions  were  in  all  cases 
colorless. 

By  testing  with  Fehling's  solution  the  oxidation  was  found  in  the 
first  three  trials  (80  cc.  hydrogen  peroxide)  to  be  complete  after  seven 
to  ten  days  and  in  the  last  three  (160  cc.  hydrogen  peroxide)  after  fourteen 
to  seventeen  days,  as  evidenced  by  the  absence  of  reduction.  While  the 
solutions  were  standing,  as  well  as  at  the  conclusion  of  the  oxidation,  the 
continued  presence  of  an  excess  of  hydrogen  peroxide  was  proved  by 
frequent  tests  with  starch  potassium  iodide  paper.  The  excess  of  hydrogen 
peroxide  was  finally  removed  by  the  addition  of  a  little  platinum  black  and 
vigorous  stirring. 

(/)  Quantitative  Determination  of  the  Amounts  of  Carbon  Dioxide  Formed 
in  the  Oxidation. — To  determine  the  amount  of  carbon  dioxide  in  each 
case,  an  apparatus  was  set  up  in  which  a  wash  bottle  of  concentrated 
potassium  hydroxide  was  connected  with  a  large  U-tube  filled  with  soda 
lime,  and  this  in  turn  with  the  flask  containing  a  sugar  solution.  To  the 
other  side  of  the  flask  was  attached  a  reflux  condenser  in  series  with  six 
towers  containing  a  saturated  solution  of  barium  hydroxide.  The 
calculated  amount  of  hydrochloric  acid  was  then  added_to  the  alkaline 
reaction  mixture  by  means  of  a  dropping  funnel,  and  air  free  from  carbon 
dioxide  was  slowly  and  continuously  drawn  through  the  apparatus. 
The  flask  was  finally  heated  in  an  oil  bath  at  110°  to  120°  for  one  hour. 
The  barium  carbonate  precipitate  was  then  thoroughly  washed,  dried  at 
1 00°  and  weighed. 

Blank  experiments  were  also  made  to  determine  the  amount  of  carbon 
dioxide  in  5.62  g.  of  potassium  hydroxide.  Three  determinations  gave 
respectively,  0.2430  g.,  0.2439  g.  and  0.2435  g.  of  barium  carbonate. 

The  three  solutions  of  maltose  with  80  cc.  of  hydrogen  peroxide,  after 
the  correction  was  made  for  the  potassium  hydroxide,  gave  respectively, 
0.8584  g.,  0.8556  g.  and  0.8540  g.  of  barium  carbonate.  Two  of  the 
solutions  prepared  with  160  cc.  hydrogen  peroxide,  after  the  correction, 
gave  0.9851  g.  and  0.9629  g.  of  barium  carbonate. 

TABLE  I. — SUMMARY  OP  RESULTS  FOR  CARBON  DIOXIDE. 

Amount         Amount  of  hy-       Time  for  Grams  of 

of  maltose,     drogen  peroxide,     oxidation.  carbon  Per  cent,  of        Percent,  of 

Grams.  Cc.  Days.  dioxide.  theoretical  yield.        total. 

3.22  80  y-IO  0.137  2-91  4-52 

3.22  80  7-10  0.134  2-84  4.41 

3.22  80  7-10  0.136  2.85  4.47 

3.22  160"  14-17  0.220  4.67  7.21 

3.22  160  14-17  0.215  4.56  7.05 


(2)  Quantitative  Determination  of  the  Amounts  of  Volatile  Acids. — As 
before,  three  lots  of  3.22  g.  of  maltose  with  80  cc.  hydrogen  peroxide 
were  set  aside  under  like  conditions,  also  three  lots  with  160  cc.  hydrogen 
peroxide.  The  time  periods  for  complete  oxidation  were  the  same  as  in 
the  first  series.  After  adding  the  platinum  black  to  the  solutions  and 
heating  the  flasks  to  remove  the  excess  of  hydrogen  peroxide,  theoretical 
amounts  of  hydrogen  chloride  were  added.  Each  solution  was  then 
separately  distilled  from  a  flask  provided  with  a  Kjeldahl  bulb  to  prevent 
the  volatilization  of  possible  gly collie  acid.  A  pressure  of  10-25  mm. 
was  maintained  and  the  flask  finally  heated  for  some  time  in  a  boiling 
water  bath.  The  residues  were  several  times  dissolved  in  100  cc.  of  water 
and  the  distillation  repeated.  The  distillate,  which  proved  to  be  free 
from  hydrogen  chloride,  was  then  made  up  to  a  definite  volume  and  the 
formic  acid  determined  by  titrating  an  aliquot  part  with  o.i  N  sodium 
hydroxide.  The  Jones1  method  was  also  used,  in  which  the  formic  acid 
was  oxidized  to  carbon  dioxide  with  o.i  N  permanganate.  The  two 
methods  agreed  perfectly,  thus  proving  formic  the  only  volatile  acid 
present. 

TABLE  II. — SUMMARY  OF  RESULTS  FOR  FORMIC  ACID. 

Amount  of  Formic  acid  Formic  acid 

Amount  of        hydrogen  Time  for         by  per-  by  sodium  Per  cent,  of  Per  cent, 

maltose.           peroxide.  oxidation,  manganate.  hydroxide.  theoretical  of  total 

Grams.                  Cc.  Days.             Grams.             Grams.  yield.  weight. 


7  22 

80 

7—10 

i  .377 

27.84 

44.QO 

o  •  *  * 

3.22 

80 

7-10 

1-336 

1-334 

*  /  *  V*T 

27.14 

~r*r  y~* 
43.80 

3.22 

160 

14-18 

2.070 

2.065 

42  .00 

67-85 

3.22 

1  60 

14-18 

2  .OO7 

2  .OI2 

40.60 

65.55 

1  .22 

1  60 

I4.-I8 

2  .04.  7 

4.1  .4.O 

66  .  8.s 

(j)  The  Nonvolatile  Acids. — In  the  determination  of  the  nonvolatile 
acids  left  behind  with  the  salt  residue  after  the  distillation  of  formic  acid, 
it  was  decided  to  use  larger  quantities  of  the  materials  in  the  same  pro- 
portion as  in  the  preliminary  experiments,  in  which  80  cc.  hydrogen 
peroxide  were  used.  Eight  25.76  g.  lots  of  maltose  (equivalent  to  195.77 
g.  of  anhydrous  sugar)  were  thus  set  aside.  In  each  case  the  strength  of 
the  hydrogen  peroxide  was  again  determined  just  before  using  and  correc- 
tion made  so  as  to  keep  the  concentration  uniform.  No  change  in  the 
temperature  or  color  of  the  solution  was  ever  noticed  on  addition  of  the 
hydrogen  peroxide  solution  to  the  sugar.  There  were  only  slight  differ- 
ences in  the  time  required  for  complete  oxidation,  the  average  being  eleven 
days.  After  no  reduction  was  shown  with  Fehling's  solution,  the  con- 
tents of  each  flask  were  heated  for  a  half  hour  and  shaken  repeatedly 
with  platinum  black  to  remove  the  excess  of  hydrogeivperoxide.  Then 
6%  in  excess  of  the  theoretical  amount  of  hydrochloric  acid  was  added, 
and  the  solution  distilled  at  a  temperature  of  45  ?  to  50  °  under  a  pressure 
1  Am.  Chem.  J.,  17,  539. 


IO 

of  15-25  mm.  The  residue  in  the  flask  was  dried  at  80°  for  half  an  hour, 
redissolved  in  150  cc.  water  and  again  distilled.  This  process  of  re- 
distillation was  continued  until  the  nonvolatile  acids  were  entirely  free 
from  hydrogen  chloride. 

The  amount  of  formic  acid  in  the  filtrate  from  each  lot  was  determined 
by  the  Jones  method,  the  yields  being  as  follows:  13.20  g.,  13.48  g.,  13.70 
g.,  14.19  g.,  13.50  g.,  13.45  g-»x  13-28  g.,  and  13.67  g.,  respectively.  These 
results  are  nearly  25%  higher  than  those  obtained  with  small  quantities 
of  sugar. 

The  salty  residues  of  acid  gum  from  each  lot  of  sugar  were  taken  up  in 
95%  alcohol,  thus  separating  most  of  the  potassium  chloride.  The  95% 
alcohol  residues  from  each  lot  were  then  combined  and  refluxed  with 
absolute  alcohol,  thus  eliminating  more  of  the  salt.  After  filtering  and 
concentrating  somewhat,  the  filtrate  was  left  at  a  low  temperature  for 
twenty-four  hours.  A  little  more  of  the  salt  separated  out,  together  with 
a  small  amount  of  material  which  reduced  Fehling's  solution  and  which 
apparently  was  hydrolyzed  sugar. 

The  final  product,  dried  at  75°  and  20  mm.,  weighed  105  g.,  which  is 
53.6%  of  the  weight  of  the  sugar  used. 

The  gums,  which  were  slightly  darkened,  were  dissolved  in  five  parts  of 
5%  sulfuric  acid  and  heated  on  the  boiling  water  bath  for  ten  hours  under 
the  reflux.  Then  the  theoretical  amount  of  barium  hydroxide,  necessary 
to  remove  the  acid,  was  dissolved  in  300  cc.  of  hot  water  and  slowly 
added.  After  heating  on  the  boiling  water  bath  for  another  half  hour 
the  mixture  was  filtered.  On  concentrating  the  solution  to  two  liters, 
the  amount  of  split  off  sugar  was  determined  by  the  Munson  and  Walker1 
method  and  also  by  the  Fehling  solution  method.  The  results  by  the 
former  in  two  determinations  were  0.3808  g.  and  0.3812  g.  of  cuprous 
oxide.  This  weight  of  cuprous  oxide  from  8  cc.  of  the  solution  corresponds 
to  178.4  mg.  of  dextrose,  equivalent  to  44.6  g.  of  this  sugar  in  the  2000 
cc.  By  the  latter  method  20  cc.  of  the  sugar  solution  were  diluted  to  100 
cc.  and  11.20  cc.  of  this  were  required  for  10  cc.  of  Fehling's  solution, 
corresponding  to  a  total  of  45.0  g.  of  dextrose. 

In  order  to  determine  to  what  extent  dextrose  was  destroyed  during 
the  ten  hours  hydrolysis  with  five  parts  of  5%  sulfuric  acid,  an  inde- 
pendent experiment  was  conducted  in  which  100  g.  of  c.  P.  dextrose 
hydrate  (90.90  anhydrous)  was  refluxed  on  the  boiling  water  bath  ten 
hours  with  500  cc.  of  5%  sulfuric  acid.  The  solution  darkened  and 
showed  a  final  content  of  80.12  g.  of  anhydrous  dextrose  (91.43  g.  hydrated) 
or  a  loss  of  8.56%. 

The  solution  was  now  adjusted  so  that  a  few  drops  gave  the  slightest 
precipitate  with  a  2%  solution  of  sulfuric  acid,  filtered  and  concentrated 
1  J.  Am.  Chem.  Soc.,  28,  663;  29,  541. 


II 


to  about  1500  cc.  To  remove  the  dextrose,  the  solution  was  heated 
in  a  boiling  water  bath  with  60  g.  of  calcium  carbonate  for  ten  hours  and 
filtered.  The  filtrate  was  of  a  golden  red  color  and  syrupy  odor.  Thirty- 
eight  grams  of  calcium  carbonate  were  filtered  off  and  digested  with  5% 
acetic  acid.  An  insoluble  residue  was  left  which  was  dissolved  in  hydro- 
chloric acid  and  reprecipitated  with  ammonia  several  times  until  per- 
fectly white.  This  gave  0.3047  g.  of  calcium  oxalate.  When  dried  to  a 
constant  weight  at  100°  and  analyzed  the  following  result  was  obtained: 
0.3047  g.  of  the  salts  gave  on  ignition  0.1168  g.  CaO. 

Calculated  for  CaC2O4-H2O:  CaO,  38.39;  found,  38.33. 

The  aqueous  solution  of  lime  salts  and  dextrose  was  then  concentrated 
in  two  hemispherical  evaporating  dishes  on  steam  baths.  Cold  dilute 
alcohol  was  added  with  much  stirring  and  decanted  several  times.  The 
darkened  lime  salts  thus  obtained  were  taken  up  in  water  and  decolorized 
with  animal  charcoal.  On  repetition  of  the  above  process  the  lime  salts 
became  granular  in  appearance  and  so  free  from  sugar  that  0.5  g.  showed 
no  reduction  with  Fehling's  solution.  The  air-dried  lime  salts  weighed 
60.7  g.  and  on  ignition  0.3978  g.  of  calcium  salts  gave  0.0718  g.  or  18.05% 
calcium  oxide. 

The  calcium  was  split  off  by  treating  the  lime  salts  in  a  hot  dilute  solu- 
tion with  a  slight  excess  of  oxalic  acid.  After  filtering,  the  aqueous 
solution  was  distilled  under  reduced  pressure,  as  usual,  and  the  residue 
dried.  The  thin  syrupy  acids  which  weighed  40.5  g.  dissolved,  with  the 
exception  of  0.3  g.,  in  500  cc.  hot  absolute  alcohol.  This  solution  was 
concentrated  several  times  and  set  aside  in  the  ice  box,  but  no  crystals 
formed.  Finally  it  was  concentrated  to  a  weight  of  80  g.,  representing 
40  g.  of  gums  and  40  g.  of  alcohol.  There  were  now  added  slowly  250 
cc.  of  absolute  ether  with  much  shaking  and  the  whole  mixture  placed 
in  the  ice  box  over  night.  On  decanting  the  ether  solution  and  distilling, 
30.9  g.  mobile  light  brown  residue,  Fraction  A,  was  obtained.  The 
portion  insoluble  in  absolute  ether  was  darker  and  thicker  and  weighed 
9.1  g.  To  the  latter  was  added  acetic  ether  in  repeated  portions  of  300  cc. 
each,  and  the  mixture  refluxed  till  no  more  of  the  gum  went  into  solution. 
The  acetic  ether  solution  was  concentrated  and  set  away  but  no  crystals 
formed.  Finally  the  ether  was  removed  by  distillation  and  8  g.  of  gum, 
Fraction  B,  obtained.  The  remaining  gum,  Fraction  C,  soluble  in  ab- 
solute alcohol  weighed  0.9716  g. 

Fraction  A. — On  standing  for  some  time  after  careful  drying,  the  entire 
ether  residue  weighing  30.9  g.,  solidified  to  a  homogeneous  mass  of  leafy 
crystals  characteristic  of  glycollic  acid.  Its  identity  wittl  this  acid  was 
established  in  five  different  ways. 

The  melting  point  of  the  crystals  was  found  to  be  So0.1 
1  Nef,  Ann.,  357,  223. 


12 

A  portion  was  carefully  dried  in  a  vacuum  desiccator,  weighed  and 
dissolved  in  water.  A  part  of  this  solution,  equivalent  to  0.2678  g.  of 
crystals,  on  titration  required  34.72  cc.  of  o.i  N  sodium  hydroxide,  or 
64.8  cc.  for  0.5  g.  The  theoretical  amount  required  for  0.5  g.  of  glycollic 
acid  is  65.8  cc. 

To  4.1  g.  of  A  was  added  4  cc.  50%  alcohol  and  7.09  g.  of  phenyl  hy- 
drazine.  After  standing  three  or  four  days  at  room  temperature  the 
mixture  suddenly  became  a  mass  of  fine  crystals.  These  were  filtered 
off  and  recrystallized  twice  from  30%  alcohol.  Three  and  one-tenth 
grams  of  shiny  hexagonal  plates  with  a  melting  point  of  ioo01  were  ob- 
tained. 

Four  and  six-tenths  grams  of  the  crystals  from  the  residue  A  were 
digested  eight  hours  on  a  boiling  water  bath  with  5  g.  of  quicklime.  An 
excess  of  5  g.  of  calcium  hydroxide  was  filtered  off.  On  concentration 
of  the  filtrate,  3.4  g.  of  crystals  of  calcium  glycollate  were  obtained  and 
recrystallized.  i.oioo  g.  of  air-dried  salt  lost  on  drying  to  constant 
weight  at  100°  to  120°  0.2838  g.  of  water. 

Calculated  for  Ca(C2H3O3).4H2O:  H2O,  27.48;  found,  28.09. 

The  remaining  0.7266  g.  of  anhydrous  calcium  salt  gave  on  heating 
0.2126  g.  of  CaO. 

Calculated  for  Ca(C2H3O3):  CaO,  29.47;  found,  29.27. 

Four  and  five-tenths  grams  of  the  residue  A  on  being  treated  with  an 
excess  of  strychnine  in  the  usual  manner  gave  on  crystallization  8.0  g. 
strychnine  glycollate  melting  at  185°  to  iQO0.2 

On  heating  the  strychnine  glycollate  with  an  excess  of  quicklime  for 
ten  hours  there  was  obtained  3.4  g.  of  calcium  salt.  1.2125  g.  of  air-dried 
salt  lost  on  being  dried  in  the  air  bath  to  constant  weight  as  above  0.3420 
g.  of  water. 

Calculated  for  Ca(C2H3O3)4.H2O:  H2O/27.48;  found,  28.20. 

The  remaining  salt,  0.8705  g.,  gave  on  further  heating  0.2550  g.  of 
CaO. 

Calculated  for  Ca(C2H3O3):  CaO,  29.47;  found,  29.29. 

Fraction  B. — This  residue  of  8.0  g.  was  diluted  with  water  to  250  cc. 
Ten  cc.  of  this  solution  containing  0.32  g.  of  the  original  gum  was  diluted 
to  ioo  cc.  and  treated  with  49.8  cc.  o.i  N  sodium  hydroxide.  This  was 
heated  for  ten  minutes  on  the  boiling  water  bath  and  the  excess  of  sodium 
hydroxide  titrated  with  o.i  N  hydrochloric  acid.  A  total  of  23.19  cc. 
o.i  N  sodium  hydroxide  was  thus  used  to  neutralize  0.32  g.  of  the  acid. 
On  the  basis  of  this  titration,  the  calculated  amount  of  brucine,  25.5  g., 
was  added  to  the  acid  solution,  together  with  a  small  amount  of  alcohol. 

1  Ann.,  357.  233. 

2  Nef,  Ibid.,  357,  238. 


13 

This  was  digested  on  the  boiling  water  bath  one  hour  after  the  complete 
solution  of  the  brucine.  On  concentrating  the  solution  under  reduced 
pressure  a  white  precipitate  of  5.1  g.  formed  which  was  filtered  off  and 
proved  to  be  brucine.1  The  water  was  removed  by  distillation  and  the 
residue  taken  up  in  half  its  weight  of  water  and  five  times  its  weight  of 
absolute  alcohol,  after  which  seven  crops  of  crystals,  totalling  20  g.,  were 
obtained  as  follows:  5  g.,  1.9  g.,  1.5  g.  and  i  g.  of  transparent  plates, 
melting  respectively  at  198-202°,  195-202°,  202-205°  and  190°;  8  g., 
1.6  g.  and  i  g.  of  small  cubes  all  melting  at  175°. 

Fraction  C. — This  alcohol-soluble  residue  of  0.9716  g.  was  diluted  with 
water  to  100  cc.  and  titrated  as  above.  Ten  cc.  of  the  solution  required 
7.25  cc.  of  o.i  N  sodium  hydroxide.  To  the  remaining  solution  was 
added  the  calculated  amount  of  brucine,  2.85  g.  On  taking  up  the  salts 
in  alcohol  0.2  g.  melting  at  184°  and  0.2  g.  melting  at  185°  crystallized 
out.  After  concentration  a  residue  of  1.5  g.  was  left  which,  combined 
with  a  corresponding  residue  from  Gum  B,  made  9.5  g.  In  order  to 
convert  this  combined  residue  into  free  brucine  and  acid,  sodium  hydroxide 
was  added  on  the  basis  of  one  and  one-half  molecules  of  sodium  hydroxide 
to  one  molecule  of  the  brucine  salt  of  an  assumed  four-carbon  atom  acid. 
Eight  grams  of  brucine  were  filtered  off.  To  neutralize  the  sodium 
hydroxide  a  slight  excess  of  hydrochloric  acid  was  added  and  the  solution 
distilled  to  dryness.  The  salty  residue  was  dissolved  in  water  and  re- 
distilled to  remove  all  traces  of  hydrogen  chloride.  The  acid  was  then 
taken  up  in  absolute  alcohol  and,  after  the  removal  of  the  alcohol,  2.052 
g.  of  gum  were  obtained.  This  residue  was  titrated  as  before  in  a  2% 
solution  and  0.5  g.  was  found  to  require  38.49  cc.  o.i  N  sodium  hydroxide. 

The  remaining  portion  of  the  solution  was  digested  eight  hours  on  the 
boiling  water  bath  with  3.3  g.  of  quicklime.  The  filtrate  on  standing 
gave  0.7869  g.  of  crystals.  On  heating  these  to  a  constant  weight  0.7245 
g.  was  obtained.  After  ignition  0.1102  g.,  or  10.85%,  of  calcium  oxide 
was  left. 

The  high  melting  salts,  including  the  first  four  crops  from  B  and  the 
two  small  crops  from  C,  were  combined,  making  9.8  g.  in  all.  Likewise 
the  remaining  low  melting  salts  from  B  were  combined,  making  10.6  g. 
On  treatment  with  sodium  hydroxide  in  the  usual  way  the  high  melting 
salts  gave  2.4  g.  of  acid  gum  and  the  low  melting  salts  3.2  g.  On  stand- 
ing, after  having  been  freed  from  absolute  alcohol  by  distillation,  the 
low  melting  salts  gave  0.52  g.  of  leafy  crystals  resembling  in  appearance 
glycollic  acid  and  melting  at  79°.  This  was  boiled  with  strychnine,  and 
after  filtering  off  the  excess  gave,  on  concentration,  0.2.5.  of  strychnine 
glycollate  crystals  melting  at  185°.  The  remainder  of  the  solution  of 
this  residue  was  added  to  a  similar  residue  from  the  high  melting  salts. 
1  Anderson.  Am.  Chem.  J .,  42,  410  (foot-note)  (1909). 


H 

The  2.4  g.  of  gum  from  the  low  melting  salts,  on  being  taken  up  in  alcohol 
and  allowed  to  stand  for  some  time,  gave  0.32  g.  of  the  characteristic 
crystals  of  mannonic  lactone  melting  at  150°.  Some  of  this  was  mixed 
with  pure  mannonic  lactone  with  no  change  in  melting  point. 

After  various  futile  attempts  at  identification,  the  remaining  portion 
from  the  low  melting  salts  was  combined  with  that  from  the  high  melting 
salts,  giving  2.32  g.  An  optical  determination  of  the  latter  gave:  d  = 
1.054;  P  =  2>  i-  e->  °-5223  g-  substance  and  25.5927  g.  water;  [a]  in  a 
i  dcm.  tube  equals  — 0.70°;  whence  [a]2D°  =  — 33-20.1  Of  the  residual 
gum  0.5  g.  was  found  to  require  37.55  cc.  o.i  N  sodium  hydroxide.  With 
quicklime  the  final  portion  gave  0.8364  g.  air-dried,  calcium  salt.  This, 
on  drying  to  constant  weight,  lost  0.0886  g.  or  10.5%  water.  On  ignition 
0.1271  g.,  or  17%  of  CaO  was  obtained. 

Summary. 

1.  Saccharinic  acid  formation  does  not  take  place  at  room  temperature 
when  maltose  is  treated  with  an  alkaline  solution  of  hydrogen  peroxide 
with  an  alkalinity  of  0.43  N. 

2.  The  ratio  and  nature  of  the  oxidation  products  from  maltose  with 
alkaline  peroxide  are  quite  different  from  that  of  glucose  with  the  same 
reagent,  a  fact  which  must  be  attributed  to  the  effect  of  the  glucosido 
bond. 

3.  Approximately  half  of  the  maltose  in  the  reaction  mixture  used, 
oxidizes  as  such.     The  remainder  is  apparently  hydrolyzed  before  oxida- 
tion. 

4.  The  formation  of  glucosido  acids  in  the  oxidation  of  maltose  ex- 
plains why  a  molecule  of  dextrose  requires  2.48  atoms  of  oxygen  by 
Fehling's  solution  while  the  larger  maltose  molecule  requires  but  2.86 
atoms  with  the  same  reagent. 

5.  The  formation  of  a-  and  /3-d-isosaccharinic  acids  from  maltose  under 
the  influence  of  mild  alkalies  involves  free  hydroxyl  groups  on  the  first, 
second  and  third  carbon  atoms  from  the  free  aldehyde  group.     These 
carbon   atoms   are   therefore   eliminated   as   having   taken   part   in   the 
glucosido  bond. 

6.  The  formation  of  relatively  large  amounts  of  7-d-glucosidogly collie 
acid  in  the  oxidation  of  maltose  rather  than  7-d-glucosidoglycerinic  acid 
indicates  that  the  terminal  or  primary  alcohol  carbon  atom  functions 
in  the  glucosido  union  of  the  two  d-glucose  molecules  which  go  to  make 
up  maltose. 

7.  The  formula  of  maltose  is  that  of  a  7-d-glucosido-d-glucose  with  the 
glucosido  union  on  the  primary  alcohol  carbon. 

1  Glattfeld,  Am.  Chem.  J.,  50,  150. 


15 

8.  It  is  probable  that  maltose  under  the  influence  of  alkalies  enters 
into  an  equilibrium  of  the  six  glucosido-hexoses  of  the  glucose  series,  the 
dissociation  and  oxidation  of  whose  intermediate  hexose-dienols  result 
in  the  various  oxidation  products  found. 

This  work  was  done  under  the  direction  of  Dr.  W.  Lee  Lewis,  grateful 
acknowledgment  of  whose  constant  help  and  encouragement  is  here  made. 


r 

OVERDUE. 


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